I've been looking at WordPress plugins to rotate header images automatically, at the moment there's nothing that does quite what I want, which is this:

By default, randomly rotate the images from a selection in a folder (this can be done by several plugins)

On certain days (user-settable) a particular image would be used. I'd be able to have several such special images. Ideally I'd be able to specify whether the day was in my time zone, the server's time zone or the time zone of the user. (Probably on a global basis, if this were on a per image basis there is the potential for conflict, though this could be result by randomising the image choice. Indeed, this would mean that events which occured on the same day could both be commemorated. One might specify a priority (i.e. in the event of conflict, give this picture priority)

By default, these images wouldn't be used in the random rotation at other times of the year, though this could be over-ridden on a per-image basis.

Perhaps, the images could come with their own preferences for other text to be pasted in before and after with them (this would allow me to have one tiled, one float right and the another fixed left). Of course, there would be some default which is user-settable. (The result of this is that the user could surround their image link with whatever they wanted, img tags, css, whatever).

The icing on the cake would be to be able to specify things like 'This image is used EVERY 5th August', 'This image to be used on the second monday of august', 'This image to be used on 5th august 2006 and then every four years', 'This image to be used on 31st August 2007' (one month after that date the reference would be removed).

In the template I'd wrap the whole lot in an 'if this function exists then... else...' statement, including my existing static image in the else statement so the plugin could be disabled without breaking things.

I wonder, and hope, that there is someone who knows about WordPress plugins out there that thinks 'Ooh, what a good idea, let's code it' - or 'That plugin already exists, let's comment about it'. Fingers crossed.